41.   State Trooper William Serpa, the first trooper to arrive on the scene, said the carnage left rescue crews shaken.

42.   That is bad for rescue crews and for anyone clinging to life and gasping for oxygen under the debris.

43.   The chemical industry has a tracking system for monitoring shipments of dangerous chemicals, designed mainly to alert rescue crews to the contents of particular trucks involved in accidents.

44.   The effort was led by Morrisville Fire Chief Tony Chiocakis, who said rescue crews found people alive both inside and outside the plane.

45.   The effort was led by Morrisville Fire Chief Tony Chiocakis, who said rescue crews found people alive inside and outside the plane.

46.   The officer was ready to summon rescue crews to begin dragging the lake for a body.

47.   The office workers were said to have communicated with colleagues above ground, perhaps by cell phone, helping rescue crews pinpoint their whereabouts.

48.   The rescue crew went down the ropes and took the climbers back to the top with them.

49.   The utility crews have to work around rescue crews and their equipment, and several times have had to flee when building collapses were anticipated.

50.   The work of rescue crews was eased somewhat because the train ground to a halt directly in front of an access gate through fencing.